Formula One Aerodynamics (Part 1)
I am still fascinated by those upright wings on the BMW Sauber. It may well be that they give the car more stability under braking, as claimed, but they also illustrate the weirdness of modern aerodynamics.
Now that everyman and his dog has a wind tunnel, we see a lot of strange protuberances on F1 cars and it’s hard to see what some of them achieve. Renault even say that they don’t know what the little flip-up ears on the nose of the R26 do; they’re just there in case they help.
So the Renault has its ears, the Ferrari has a nose plug and the McLaren has grown horns, and who can say how they make the car faster? Apparently they do, however, as the Toyota attests; it has variants of all three.
One thing we do know is that all these winglets have to do with keeping the air flow smooth and in the right places. Turbulence causes drag and so the idea is to keep the flow smooth until it reaches the most aerodynamically important part of the car: the rear. Since the FIA have decreed that F1 cars should have flat undertrays until they reach the line of the rear axle, the aerodynamicist is left with a very small area to work with, essentially from the back axle to the rear wing. And, to maximize your tweaks in this area, you need a smooth and predictable flow of air arriving from the front of the car.
The irony is that being first with a new idea does not guarantee success. The most visible instance of this today is the raised nose, first seen on the Tyrrell 019 in 1990.
It was the Tyrrell team’s last hope as they faded towards the back of the F1 grid but it didn’t help them at all. The other teams worked out what the idea was, tried it in their wind tunnels and came out with better implementations. And now all the cars have raised noses while Tyrrell is F1 history.
So why is that raised nose so necessary? Essentially, it’s to do with the business of getting smooth air to the back of the car but also to persuade as much air as possible to go over or around the car, rather than under it. By raising the nose, you allow air to flow straight to the central section above the undertray. At that point, it is separated into two flows, one on each side and controlled by barge boards and winglets. But, by extending the undertray forward a little to form a lip, you can prevent the air from taking the third available route – under the car.
You want as little air under the car as possible; this encourages the formation of a low pressure area there that can then be increased with all your flip-ups and vanes at the rear.
Most of the aerodynamic measures we see at the front of the F1 car are intimately linked with what the air is destined to do at the back. Only the front wing provides large amounts of downforce and this can be altered to balance with the downforce provided by the rear wing.
Aerodynamics is an arcane science and gives rise to some strange formations in F1 cars. I can only guess at what some of the shapes at the rear achieve but we could look at the more obvious stuff in a later post. For the moment, it is sufficient to note that, even if BMW Sauber’s innovation does work, they won’t necessarily be the ones to benefit most from it. Such is life in Formula One.